Route planning system and method for minimizing exposure to threats

ABSTRACT

The present invention relates to a system and method for route planning. The system is arranged to be mounted on a moving object. The system comprises a route planning module arranged to plan a route of the object upon request, wherein occasions of being visible from any point in the map within a shooting range during a predetermined time period is minimized. The system is characterized in that the route planning module is arranged to determine areas in the 3D map in which the object will be exposed to a potential threat during a predetermined time period based on line of sight calculations, and determining a re-planned route avoiding said potential threat areas.

TECHNICAL FIELD

The present invention relates to a system and a method for re-routeplanning.

BACKGROUND ART

There is known in the art for route planning and re-route planning.

U.S. Pat. No. 7,848,879 shows a system for determining a course ofaction for an aerial vehicle. The system handles different type ofthreats. The threats are related to a predetermined threshold time formaximum safe visibility by a vehicle. The system is arranged to detectthreats, to store a planned route for the vehicle, to determine types ofthreats detected and to utilize the predetermined threshold times to foreach threat detected by the vehicle to determine whether the plannedroute may safely enter visibility range of each threat detected by thevehicle and to determine a first elapsed time that the planned routebrings the vehicle within the visibility range of a first threatdetected by the vehicle.

SUMMARY OF THE INVENTION

One object of the present invention is to enable improved routeplanning.

This has in accordance with one example been achieved by means of asystem for route planning arranged to be mounted on a moving object. Thesystem comprises a route planning module arranged to plan a route of theobject upon request, wherein occasions of being visible from any pointin the map within a shooting range during a predetermined time period isminimized. The route planning module is arranged to determine areas inthe 3D map in which the object will be exposed to a potential threatduring a predetermined time period based on line of sight calculations,and determining a re-planned route based on exposure to said potentialthreat areas.

In one option, the system further comprises a communication modulearranged to transmit firing area data to other objects and/or to receivefiring area data from other objects.

In one option, the route planning module is arranged to receiveinformation related to identified threat areas from the communicationmodule and to calculate the re-planned route based on these identifiedareas. The identified threat areas may comprise the firing areas.

In one option, the route planning module is arranged to determine safeareas in the 3D map in which the object will be exposed during apredetermined time period from a safe location in the map, anddetermining a re-planned route based on said safe areas.

In one option, the system comprises a position module and a firerlocation estimation module. The position module is arranged to registerthe present position of the moving object at the request and todetermine the travel path of the moving object during a predeterminedtime period preceding the request, wherein the present positionrepresents a target position for firing. The firer location estimationmodule is arranged to estimate the location of a firer based on theregistered position and the determined travel path and based on map datacomprising 3D geographical coordinate data. The route planning module isthen arranged to plan a route of the object based on the determinedlocation of the firer.

In one option, the moving object is a ground based object.

In one option, the moving object is a vehicle.

In one option, the firer location estimation module is arranged toestimate the location of the firer based on line of sight calculationsusing the assumption that the object has been visible to the threatsubstantially during the whole predetermined time period.

In one option, the route planning module is arranged to determine afiring area reachable from the estimated firer location based on the 3Dmap data and line of sight calculations, and to plan the route so as toavoid said firing area.

In one option, the route planning module is arranged to re-plan theroute based on the extent of the firing area and based on the 3D mapdata.

In accordance with one example, the invention also relates to a methodfor re-route planning for an object moving according to a route to aplanned destination. The method comprises the steps of determiningpotential threat areas in a 3D map in which the object will be exposedto a potential threat during a predetermined time period based on lineof sight calculations, and determining a re-planned route based on saidpotential threat areas.

In one option, the method comprises a step of determining threat areasin which the object will be exposed to an identified threat during apredetermined time period, and determining a re-planned route based onsaid threat areas.

In one option, the calculation of the re-planned route comprisesdetermining safe areas in the map in which the object will be exposedduring a predetermined time period from a safe location in the map, anddetermining a re-planned route based on said safe areas.

In one option, the re-route planning is based on terrain constraintssuch as hills, rivers, forests or other obstacles which may prevent theobject from moving unhindered.

In one option, the re-planned route is calculated based on timeconstraints.

A computer programme comprises a programme code for re-route planningfor an object moving according to a route to a planned destination. Thecomputer program comprises the steps of determining potential threatareas in a 3D map in which the object will be exposed to a potentialthreat during a predetermined time period based on line of sightcalculations, and determining a re-planned route based on said potentialthreat areas.

A computer programme product may comprise a programme code stored on a,by a computer readable, media for re-route planning for an object movingaccording to a route to a planned destination. The computer programme isarranged to execute the steps of determining potential threat areas in a3D map in which the object will be exposed to a potential threat duringa predetermined time period based on line of sight calculations, anddetermining a re-planned route based on said potential threat areas,when said computer programme is run on a computer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the topology of a terrain with a vehicle moving alonga path in the terrain.

FIG. 2 illustrates a determined location a firer in the terrain.

FIG. 3 illustrates a determined shooting area in the terrain.

FIG. 4 illustrates a re-route around the shooting area.

FIG. 5 illustrates identified threats marked in a 3D map of a terrain.

FIG. 6 illustrates potential threats marked in a 3D map of a terrain.

FIG. 7 is a block scheme for an example of a system for route planning.

FIG. 8 is a flow chart illustrating an example of a method fordetermining the location of a firer.

FIG. 9 is a flow chart illustrating an example of a method for routeplanning.

FIG. 10 is a flow chart illustrating an example of steps performed forre-planning a route.

FIG. 11 is a block scheme illustrating an example of a system forproviding knowledge about the environment.

DETAILED DESCRIPTION

In FIG. 1, at least one object 101 is moving in a terrain. The objectmay be a vehicle. The vehicle may for example be a ground based vehiclesuch as heavy vehicles. The heavy vehicle may for example be a truck, abus or a tank or a ground based unmanned vehicle. The ground basedvehicle may also be a car, a motor bike etc. The vehicle may also be anaerial vehicle such as a military or commercial aircraft, an UnmannedAerial Vehicle (UAV), a helicopter etc. The moving object may be aperson. The moving object may be moving into unknown territories with nopersonal knowledge about the terrain, roads, hostile military forcesetc. In FIG. 1, more than one vehicle is illustrated. The positions forone of the objects during a predetermined time period preceding thecurrent time are marked as a path 102.

In FIG. 11, the moving object is provided with a system 1100 forproviding knowledge about the environment. In the illustrated example,the system comprises a communication module 1111 for communication witha command and control system 1113 supporting with information abouthostile forces and their locations and movements, about areas withlimited navigability etc. For example, some roads can carry less heavyvehicles and some roads may hold for heavier vehicles. Further, theremay for example flooded areas where no vehicle can pass.

Further, the system may comprise storage 1101 for a 3D map and a display1109 for display of information extracted from said 3D map. The map is a3D map comprising 3D coordinate data given in a georeferenced coordinatesystem. The 3D map may further be textured. The 3D map comprises a 3Dmodel of the environment. The 3D model may comprise substantially allvisible surfaces (above a certain size) in the environment seen from anyangle. Thus, substantially all surfaces in the environment exceeding acertain size are associated to 3D coordinate data given in thegeoreferenced coordinate system. Further, also texture data may beassociated to all surfaces in the environment exceeding a certain size.The geo-referenced coordinate data may comprise latitude data, longitudedata and height data and may be associated to texture information. Thedata may have an accuracy of one or a few meters, preferably in therange of decimetres. In one example, the accuracy is one decimetre orhigher. The required accuracy in the model depends on the size of theobject moving in the terrain. To sum up, the 3D map provides a correctcoordinates in a georeferenced coordinate system.

The display 1109 may be arranged to present 3D map data so as to supportselection of a route which is as safe as possible. The 3D mappresentation may also be used for visualizing information related toindentified or potential threats along the route as the moving object ismoving along its route. In one example, identified threats reported infrom the command and control system may be visualized in the 3D map. Forexample, areas related to locations of identified threats may be markedon the display 1109. Also audio equipment 1112 may be present which canalarm when the moving object is approaching an identified threat asreported from the command and control system. FIG. 5 illustrates a mapwith identified threats in the terrain.

Further, the 3D map data may be processed in a processing unit 1114based on the route of the moving object. The processing may then beperformed so as to determine potential threats, i.e. areas in theterrain within reach for firing from hostile forces, where the movingobject is visible during a time period long enough so that the potentialhostile forces have time to aim and fire at the moving object. Thisprocessing is performed by estimating the route, if route data is notavailable, and based on this data perform line of sight calculations inthe 3D map to find positions/zones from which the moving object isvisible during a predetermined period long enough to perform aiming andfiring. These areas may be marked in the 3D map presented by the display1109 as potentially dangerous areas. Thus, the system 1100 for providingknowledge about the environment may provide essential information forenhancing the safety of a route of the moving object. FIG. 6 illustratespotential threats in association to a plurality of possible roadsselections.

The object may be moving according to a pre-planned route. A system forroute planning 1105 is arranged to be mounted onboard or in associationto the moving object. The system for route planning has access to a GPSreceiver 1106 and the above described 3D map data 1101, and accordinglyto 3D map data associated to a region in which the route is intended tobe performed.

Further, the system 1100 for providing knowledge about the environmentcomprises a control unit 1110. On one example, the control system isarranged to control the system to continuously follow t the object asthe object is moving. The system is arranged to use information receivedfrom a command and control system 1113 related to identified threats toalert for example via the display and/or the audio equipment whenidentified threats are approached. Further, the control unit 1110 mayalso be arranged to control processing so as to determine and alertabout potential threats as the object travels forwards along its route.As described above, the determination of potential threats involvesdetermining areas in the terrain within reach for firing from hostileforces, where the moving object is visible during a time period longenough so that the potential hostile forces have time to aim and fire atthe moving object. Line of sight calculations may be used fordetermining the potential threats.

Characteristically, the object is moving according to a planned route toa destination. The system may have access to information related to theplanned route. Further, the control unit 1110 may be arranged to receiveinstructions for example related to a new destination. The informationrelated to the new destination may be received for example from thecommand and control system 1113. Alternatively, the new destination maybe selected by way of manual input via a user interface (not shown). Theroute planning module 1105 may then be arranged to calculate at leastone potential route to the destination. The route planning may beperformed in at least two steps. In a first step, a plurality ofavailable routes are determined based on the identified threat areas.Thereafter, a cost may be associated to each of the available routes.The cost may be based on the exposure to potential threats, i.e.exposure to areas in the terrain within reach for firing from hostileforces, where the moving object is visible during a time period longenough so that the potential hostile forces have time to aim and fire atthe moving object. The cost may also be based on for example timeconstraints and/or terrain constraints and/or fuel constraints. In thecase wherein a plurality of objects are travelling together, for examplea convoy, the costs associated to each selectable route may be based onthe fact that it is a whole convoy that is moving to the destination. Inone example, the route planner may be arranged to evaluate the costs ofseparating the convoy into smaller groups taking different routes.

In one example, the route planner is arranged to present the availableroutes along with information related to the cost(s) for each route. Theinformation presented related to costs could in one example comprisetime to destination, time exposed to potential threats, closest distanceto identified threat etc. One route can then be selected based on manualinput. Alternatively, the route planning module 1105 is arranged toautomatically select one route.

In FIG. 2, a location or location zone 203 of a threat has beenestablished. We will in this disclosure denote this threat as a firer.The term firer is intended to be interpreted broadly and include forexample one single firer or a group of firers having small arms weaponsor heavier weapons, one or a group of tankers or robots or an entiremilitary set-up. The firer location has been identified based on line ofsight calculations using information related to the 3D map and thepresent position of the object and its path during the predeterminedtime period and based on the assumption that the object has been visibleto the firer substantially during the whole predetermined time period.Thus, these line of sight calculations have been used to identify one ora plurality of positions/zones from which the object has been visibleduring substantially the whole time period. If more than oneposition/zone has been identified based on the line of sightcalculations, then additional information need to be provided in orderto identify from which position/zone the firing occurred. If no suchinformation is available, then all locations/zones may be handled as afiring location/zone.

In FIG. 3, line of sight calculations has again be used in the 3D map inorder to determine a firing area 304 which can be reached by ammunitionfrom the firer based on the identified location/zone 203 of the firer,Thus, in determining the firing area, the topology of the terrain can beaccounted for by means of the 3D map. The line of sight calculations maybe based on other line of sights than a straight line. For example, aline of sight formed as a ballistic trajectory of ammunition may beused. Further, information related to the range of information used bythe firer may also be accounted for in determining the firing area. Ifno information about the ammunition is available, a preset range for theammunition may be used in determining the firing area. Additionalinformation of the firer may also be accounted for in determining thefiring area, such as movability and/or ability of re-directing theweapon. As is seen in the figure, the route 305 of the object leadsthrough the firing area 304

In FIG. 4, reroute planning has been made so as to determine a path 706or direction away from the threat based on the determined firing area.

In FIG. 5, the reroute planning comprises further finding alternativeroutes based on a plurality of identified threat areas 807.

In FIG. 6, a number of potential threat areas 908 has been determinedbased on the alternative routes and a cost has been associated to eachalternative route. As described above, the potential threat areas areareas in which the object within reach for firing and is visible for alonger time period than desirable.

In FIG. 7, a system for route planning 700 is arranged in association toan object such as a vehicle. The system is arranged to make re-routeplanning based on 3D map data 701 and based on line of sightcalculations related to the route of the object within the terrain asillustrated by the map. The system may comprise among other things aposition module 702, a firing detection module 703, a firer locationestimation module 704, and a route planning module 705.

The position module 702 is arranged to register the present position ofthe moving object at request and to determine the travel path of themoving object during a predetermined time period preceding the request.The present position may represent a target position for firing. Therequest is generated upon fire detection. A GPS receiver 706 may beoperationally connected to the position module. The GPS receiver 706 maybe arranged to feed position and optionally also time information to theposition module 702 at least upon request. Other types of receivers maybe used instead of or in addition to the GPS receiver 706 for providingcoordinate data in a geo referenced coordinate system to the positionmodule 702.

The position module 702 is in one example operatively connected to aroute log module 707. The route log module 707 records continuously thepath of the moving object. At least records from within thepredetermined time period are stored in the route log module 707.Alternatively, the whole or a major part of the route is stored in theroute log module 707. In one example, the route log module 707 isarranged to store time referenced coordinate data in the geo-referencedcoordinate system. In an alternative or complementary example, theposition module 702 is arranged to determine the travel path of themoving object during a predetermined time period preceding the requestby fetching route data from the route data storage 708 comprising routedata for the planned route. The route data storage 708 may compriseoptionally time referenced coordinate data comprising the coordinatesfor a destination, the start point and the route between the start pointand the destination.

The firing detection module 703 is arranged to detect firing at theobject. The firing detection module 703 may comprise a manuallyactivated switch, button or the like. Upon activation, a request signalis fed to the position module 702. Alternatively or in addition thereto,the firing detection module 703 may comprise an automatic fire detectionsystem automatically feeding the request signal to the position module702 upon detection of firing. In an alternative example, the firing maybe detected by a fire detection system. The automatic firing detectionsystem may for example comprise a receiver for reception of audiosignals, chock signals, image signals, radar signals etc. A signalprocessor for processing of said audio signals, chock detection signals,image signals and/or radar signals is then arranged to determine iffiring has occurred based on said signal(s). The firing detection module703 may also be arranged to determine type of ammunition and/or weapontype for the fire. The signal processor may then for example be arrangedto compare received characteristics signals with characteristics of alibrary of characteristics for different types of ammunition/weapons.Further, the signal processor for processing of said audio signals,chock detection signals, image signals and/or radar signals may bearranged to localize firing based on said signal(s).

The firer location estimation module 704 is arranged to estimate thelocation of a firer based on the registered position and the determinedtravel path during the predetermined time period. In detail, the firerlocation estimation module 704 is arranged to perform line of sightcalculations from each point of the path during the predetermined timeinterval including the present position in a 3D map comprising georeferenced coordinate data with high accuracy. The accuracy may be inthe region of decimetres. Based in these line of sight calculations,locations or zones in the 3D map are determined from which the objecthas been visible at least during parts of the path during thepredetermined time period.

The route planning module 705 may be arranged to plan a route of theobject based on the determined location of the firer. The route planningmodule may be arranged to determine the route based on the danger of thefirer and/or to plan the route so as to provide a re-planned route tothe destination or a re-planned destination. Data related to there-planned route may be stored in the route data storage 708.

The route planning module 705 is arranged to determine a firing areareachable from the estimated firer location based on the 3D map data 701and line of sight calculations, and to plan the route so as to avoidsaid firing area. These line of sight calculations may be based on aline of sight formed as a straight line or for example a ballistictrajectory. If ammunition/weapon type has been detected by the firingdetection module 703, then the route planning module 705 may be arrangedto determine the firing area also based on this information. Based onthe determined firing area and based on the 3D map data 701, a directionor path out of the firing area may be determined. This information maybe feed to a display 709 or to a control unit 710 for control of theobject.

The route planning module 705 is further arranged to determine are-planned route to the destination or a re-planned destination and tofeed data related to the planned or re-planned destination to the routedata storage 708. In detail, the route planning module 705 is arrangedto calculate a route to the planned or re-planned destination based onthe 3D map data 701, wherein occasions of being visible from any pointin the map during a second predetermined time period is minimized. Theroute planning module 705 may then be arranged to determine areas in themap in which the object will be exposed to a potential threat during apredetermined time period based on line of sight calculations, anddetermining a re-planned route avoiding said potential threat areas.

The system may comprise a communication module 711 arranged to transmitfiring area data to other objects and/or to receive firing area datafrom other objects. If data has been received related to firing areasother than that/those detected by the system for re-planning of theobject itself, this data should be taken into account in there-planning. The route planning module 705 may also be arranged todetermine safe areas in the 3D map in which the object will be exposedduring a predetermined time period from a safe location in the map, anddetermining a re-planned route based also on said safe areas.

In FIG. 8, a method for determining the location of a firer 800comprises a first step of determining the position of an object 802 atthe detection of firing against the object. The firing can in oneexample be detected by a person and thus the first step of the methodmay be manually activated. In an alternative example, the firing may bedetected by a fire detection system. In accordance with this example,the first step may be automatically activated. The firing detectionsystem may for example be audible based, based on chock detection orbased on visual detection. A combination of said detection methods canalso be used. In the first step, the position of the object is in oneexample determined by receiving and registering a coordinate from asatellite based positioning system, such as a GPS.

In a second step, a plurality of positions for the object during apredetermined time period preceding detection of the firing aredetermined, to determine the path 803. In one example, the objectarranged to log its route. The log comprises in one example timereferenced position data. The time referenced position data may bereceived from a satellite based positioning system, such as GPS. Inaccordance with this example, the positions of the object during thepredetermined time period are collected from the log during the stepsecond step. In an alternative example, route data is used for providingthe positions of the object during the predetermined time period. Thepredetermined time period is in one example a preset value based on anestimated time for detecting the object and aiming a weapon. Ifinformation is available about type of weapon and/or ammunition, thenthe predetermined time period may be selected based on that information.In one example, the selection of the predetermined time period is basedon information detected by the fire detection system.

In a third step, the possible locations of the firer are estimated 804based on 3D map data 701 and based on the position of the object at thefiring (determined in the first step 802 and the plurality of positionsof the object during the predetermined time period preceding the firingdetermined in the second step 803. The location of the firer may beestimated from line of sight calculations based on the assumption thatthe object has been visible to the threat substantially during the wholepredetermined time period. Thus, the estimation of the position of thefirer involves finding one or a plurality of positions or zones fromwhich line of sight has existed substantially during the wholepredetermined time period. The first 802, second 803 and third 804 stepsmay be continuously updated during firing so as to refine the estimatedpossible locations of the firer

In FIG. 9, a method for re-route planning 900 for an object movingaccording to a route to a planned destination comprises the followingsteps. In a first step, the possible location of a firer is determined901 based for example using the method as described in relation to FIG.5. Thereafter re-route planning is performed 902 based on the determinedpossible location of the firer 901. The re-route planning comprises aselection of or all of the steps described below.

In FIG. 10, the re-route planning 1000 first handles the threat from thedetected firer. In a firing area determination step 1001, a firing areaaround the location of the firer is determined based on the 3D map data701. Thus, this step may involve performing line of sight calculationsfrom the location of firer based on the 3D map so as to provide thetarget area. The target area may be determined based on line of sightcalculations in an area covering a full turn of 360° around the locationof the firer. Alternatively, the target area may be determined based online of sight calculations in an area covering a part of a turn aroundthe location of the firer. In one example, the line of sight is definedas a straight line. In another example, the line of sight is defined byan imagined trajectory of the ammunition in use. For example forballistic ammunition, the line of sight is defined by a ballistictrajectory.

Then, in a re-plan step 1002, the route is re-planned so as to find aroute out of the firing area which is as safe as possible. In oneexample, a control system of the object is arranged to automaticallycontrol the object in a direction leading out of the firing area. Thisinvolves calculating the direction leading out of the firing area basedon the extent of the firing area, based on physical constraints of theperformance of the object, and optionally also based on the 3D map. Inan extended example, the control system of the object is arranged tocalculate a path leading out of the firing area and automaticallycontrol the object according to this path. Alternatively, the directionis presented so that the object can be manually controlled out of thefiring area based on said presented direction. In an extended example, acomplete trajectory can be presented so that the object can be manuallycontrolled out of the firing area based on said path leading out of thefiring area. In this step, it may be necessary to re-plan thedestination for the route. If the re-routing to avoid the firing areatakes the object to a position from which it is not advisable to go toan original destination, a new destination may be selected. Thisselection may for example be based on fuel consumption, travel distanceand travel time to the destination.

When the intended destination has been established, the method forre-route planning comprises a step of determining identified threatareas 1003. In one example, wherein the re-route planning has not beencaused by firing, the method may start in this step. In the step ofdetermining identified threat areas 1003, a portion of the 3D map isselected, comprising the present position of the object and thedestination. The information related to the threat areas may for examplehave been reported in as an intelligence report from command andcontrol. Information related to threat areas can also be provided viacommunication from other objects as areas in which they have beenexposed to firing, i.e. information related to threat areas correspondto the above described firing areas. The threat areas are associated totheir locations in the selected portion of the 3D map. A number ofavailable routes can then be determined based thereon. If no informationis available related to threat areas, a number of available routes canbe determined based on other criteria such as time to destination, fuelconsumption, road conditions etc.

In a following step 1004, potential threats are identified. Thepotential threat areas are in one example identified as areas in the mapin which the object will be exposed to a potential threat during apredetermined time period based on line of sight calculations in said 3Dmap. The alternative routes may then be evaluated based on saidpotential threat areas. The re-route planning 1006 comprises thencalculating a route to said destination based on the 3D map and thepotential threat areas in said 3D map so as to minimize occasions ofbeing visible from any point in the map during a predetermined timeperiod. The time period may be selected based on a number of reasons.For example, which type of object the moving object is, velocity of theobject, information about whether the object travels alone or in a groupor a convoy.

The re-route planning can be performed in other ways than the hereindescribed, but generally avoidance of the threat areas has firstpriority and avoidance of the potential threat areas has secondpriority.

The calculation of the re-planned route may also comprise a step ofdetermining safe areas 1005 in the map in which the object will beexposed during a predetermined time period from a safe location in themap. The re-planning step is then performed based also on said safeareas.

In the re-route planning step 1006 for planning the route to thedestination, account may also be taken to terrain constraints such ashills, rivers, forests and/or other obstacles which may prevent theobject from moving unhindered. Re-route planning may in addition to theabove also be based on time constraints, fuel constraints and/or forminimize the length of the route.

The re-route planning step 1006 is in one example performed by forming aplurality of alternative routes based on the determined identifiedthreat areas, potential threat areas and safe areas. One route may thenbe selected associated to a lowest cost, wherein the costs aredetermined based on at least some of the following criteria: determinedidentified threat areas; potential threat areas; terrain constraintssuch as hills, rivers, forests and/or other obstacles which may preventthe object from moving unhindered; time constraints; fuel constraintsand/or for minimizing the length of the route.

Data associated to the re-planned route may then be fed to a system forcontrol of the object. Alternatively, the data associated to there-planned route or a plurality of available alternative routes may bepresented on a display 709 for manual control of the object based onsaid presentation. The route may also be presented as coordinate dataand control data for manual input to the control system.

A computer programme for example arranged to be executed processingmeans of the system in FIG. 11 comprises a programme code for re-routeplanning for an object moving according to a route to a planneddestination. The computer program comprises the steps of determiningpotential threat areas (1004) in a 3D map in which the object will beexposed to a potential threat during a predetermined time period basedon line of sight calculations, and determining a re-planned route basedon said potential threat areas.

A computer programme product may comprise a programme code stored on a,by a computer readable, media for re-route planning for an object movingaccording to a route to a planned destination. The computer programme isarranged to execute the steps of determining potential threat areas(1004) in a 3D map in which the object will be exposed to a potentialthreat during a predetermined time period based on line of sightcalculations, and determining a re-planned route based on said potentialthreat areas, when said computer programme is run on a computer.

The foregoing description of the preferred embodiments of the presentinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in the art. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with the various modifications as are suited tothe particular use contemplated.

1-17. (canceled)
 18. System for route planning (700) configured to bemounted on a moving object, said system comprising: a route planningmodule (705) configured to: plan a route of the object upon request, theroute being configured such that occasions of being visible from anypoint in the map within a shooting range during a predetermined timeperiod are minimized; determine areas (608) in the 3D map in which theobject will be exposed to a potential threat during a predetermined timeperiod based on line of sight calculations; and determine a re-plannedroute based on exposure to said potential threat areas (608).
 19. Systemaccording to claim 18, further comprising a communication module (711)configured to at least one of transmit firing area data to other objectsor receive firing area data from other objects.
 20. System according toclaim 18, wherein the route planning module (706) is further configuredto: receive information related to identified threat areas (507) fromthe communication module (711); and calculate the re-planned route basedon these identified threat areas (507).
 21. System according to claim18, wherein the route planning module (706) is configured to: determinesafe areas in the 3D map (701) in which the object will be exposedduring a predetermined time period from a safe location in the map; anddetermine a re-planned route based on said safe areas.
 22. Systemaccording to claim 18, said system further comprising: a position module(702) configured to: register the present position of the moving objectat the request; and determine the travel path of the moving objectduring a predetermined time period preceding the request, wherein thepresent position represents a target position for firing; and a firerlocation estimation module (704) configured to estimate the location ofa firer based on the registered position, the determined travel path,and map data (701) comprising 3D geographical coordinates data, whereinthe route planning module (705) is further configured to plan a route ofthe object based on the determined location of the firer.
 23. Systemaccording to claim 18, wherein the moving object is a ground basedobject.
 24. System according to claim 18, wherein the moving object is avehicle.
 25. System according to claim 18, wherein the firer locationestimation module (704) is configured to estimate the location of thefirer based on line of sight calculations using the assumption that theobject has been visible to the threat substantially during the wholepredetermined time period.
 26. System according to claim 18, wherein theroute planning module (705) is configured to: determine a firing areareachable from the estimated firer location based on the 3D map data(701) and line of sight calculations; and plan the route so as to avoidsaid firing area.
 27. System according to claim 18, wherein the routeplanning module (705) is configured to re-plan the route based on theextent of the firing area and based on the 3D map data (701).
 28. Methodfor re-route planning (1000) for an object moving according to a routeto a planned destination, said method comprising the steps of:determining potential threat areas (1004) in a 3D map in which theobject will be exposed to a potential threat during a predetermined timeperiod based on line of sight calculations; and determining a re-plannedroute based on said potential threat areas.
 29. Method according toclaim 28, further comprising the steps of: determining threat areas inwhich the object will be exposed to an identified threat (1003) during apredetermined time period; and determining a re-planned route based onsaid threat areas.
 30. Method according to claim 28, wherein thecalculation of the re-planned route (1000) comprises: determining safeareas (1005) in the map in which the object will be exposed during apredetermined time period from a safe location in the map; anddetermining a re-planned route based on said safe areas.
 31. Methodaccording to claim 28, wherein the re-route planning (1000) is based onterrain constraints that may prevent the object from moving unhindered.32. Method according to claim 31, wherein the terrain constraintscomprise at least one of hills, rivers, forests, or other obstacles. 33.Method according to claim 28, wherein the re-planned route (1000) iscalculated based on time constraints.
 34. A computer program product forre-route planning for an object moving according to a route to a planneddestination, the computer program product comprising at least onenon-transitory computer-readable storage medium having computer-readableprogram code portions stored therein, the computer-readable program codeportions comprising: an executable portion configured for the steps ofdetermining potential threat areas in a 3D map in which the object willbe exposed to a potential threat during a predetermined time periodbased on line of sight calculations; and an executable portionconfigured for determining a re-planned route based on said potentialthreat areas.